Slips for supporting pipe in wells



March 19, 1957 Filed Dec. 29, 1952 H. B. YOUNG SLIFS FOR SUPPORTING PIPEIN WELLS 2 Shets-Sheet l Hen/y Ben You/75} INVENTOR.

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ATTORNEYJ March 19, 1957 H. B, YOUNG 2,785,454

SLIPS FOR SUPPORTING PIPE IN WELLS Filed Dec. 29, .1952 2 Sheets-Sheet 2Henry Ben You/77 INVENTOR.

A TTOR/Vf Y5 Unite States 2,785,454 Patented Mar. 19, 1957 SLIPS FORSUPPORTING PIPE IN WELLS Henry B. Young, Houston, Tex., assignor toMission Manufacturing Company, Houston, Tern, a corporation of TexasApplication December 29, 1952, Serial No. 328,309

1 Claim. (Cl. 24263) This invention relates to new and usefulimprovements in slips for supporting pipe in wells.

This application is a continuation of my co-pending United States patentapplication, Serial No. 90,310, filed April 29, 1949, now abandoned.

Pipe gripping slips of the type employing what is known in the industryas a rolling dog construction are well known, examples of which aredisclosed in the U. S. patents to Adair, No. 1,908,652 and No.1,908,675. Such rolling dog slips employ a stack of dogs which areinclined upwardly in the slip body and which are adapted to grip a pipeto suspend same in a well or the like, but are tiltable or rollableupwardly to a small extent to release the pipe upon raising the piperelative to the slip.

In the usual rolling dog slips, each jaw of the slip hasa longitudinalrecess in the inner surface thereof into which the dogs are stacked. Thestack of dogs is generally retained in the recess by some type ofprojection or retainer which extends laterally over a portion of theupper dog in the stack so as to retain the dogs in their inclinedposition in the recess. The difiiculty with the previously known rollingdog slips is that the projection or retainer is often bent or twistedupwardly when an unintentional upward jar or blow is imparted to thedogs by the well pipe striking the dogs during upward movement of thepipe. Once the retainer is bent or twisted, the slip becomes uselessbecause the dogs are easily jarred out of the recess which results inineffective gripping of the pipe by the slips and serious jamming of thepipe in the slips due to the loose dogs. This defeet in the priorrolling dog slip assemblies has resulted in renderingmany of themworthless after a short period of use, thereby requiring their removalfor repair, with consequent expense, inconvenience and loss of drillingtime.

Another major defect in the prior known slips has been in the lack ofprotection for the slip handles against downward blows from the pipeelevators. In the usual slip construction, the handles are disposed ator near the top of the slip body and when the pipe is supported by theelevators and lowered thereby through the slips, the operator frequentlypermits the elevators to fall with such a force as to bend, crack, orotherwise damage the slip handles, so that they either become unusableor difiicult to use.

One object of this invention is to provide a slip wherein each jaw.thereof includes a body portion in which a stack of rolling dogs aresupported, together with a dog retainer mounted on the body portion forrocking or pivotal movement in accordance with the rolling or tilting ofthe dogs; said body limiting the movement of the retainer upwardly toprevent excessive upward movement: thereof which might result in bendingor otherwise deforming. said retainer.

Animportant object of this invention is to provide a slip jaw wherein astack of rolling dogs are disposed within areeess in the inner surfaceof the jaw body with the top wall of said recess being spaced above butoverhanging the uppermost dog, and a retainer rockably mounted in saidbody between the top wall of the recess and the uppermost dog in thestack whereby a sharp upward thrust, jar or blow upon the dogs istransmitted to the retainer and through said retainer directly to thejaw body to thereby protect said retainer against damage.

Another object of this invention is to provide a slip jaw body wherein astack of rolling dogs are mounted in a pocket in the body, the dogsbeing held in position by a dog retainer mounted to undergo limitedmovement on the body and resiliently urged into constant engagement withthe upper dog in the stack whereby said retainer maintains the dogs inthe body and may move or rock therewith in response to the normaltilting or rolling of the dogs; movement of the dogs beyond their normaltilting in an upward direction being prevented by the retainer reachingits limit of movement on the body.

It is another object of this invention to provide a slip dog which has adouble row of pipe-gripping teeth symmetrically disposed and also hasrounded upper and lower rear corners thereon whereby the dog isreversible.

A further object of this invention is to provide a slip jaw wherein theslip body has a handle pivotally connected thereto, with the pivotalconnection being protectedfrom impacts by a top plate of the bodyoverlying said connection.

A still further object of this invention is to provide a slip jaw havinga vertical passage disposed between a front wall in which pipe-grippingdogs are mounted and a rear wall whereby mud or slush may flowtherethrough while the dogs are gripping a pipe.

The construction designed to carry out the invention will be hereinafterdescribed together with other features thereof.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

Figure 1 is a plan view of the slip of this invention.

Figure 2 is an elevational view of the slip of this invention in itsopen position,

Figure 3 is an oblique view of one of the bodies of the slip jaws ofthis invention.

Figure 4 is an oblique view of the slip jaw illustrated in Figure 3 asviewed from the back thereof.

Figure 5 is a vertical sectional view of one of. the slip jaws of thisinvention.

Figure 6 is an exploded. view, illustrating the dog retainer and thespring therefor.

Figure 7 is a plan view of one of the slip dogs of this invention.

Figure. 8 is an elevational view of one of the slip dogs of thisinvention.

Figure 9 is a view of one of the dogs of this invention taken on line9-9 of Figure 7.

In the drawings, the letter A designates the slip of this inventionwhich includes a central slip jaw lit and two end jaws i1 and 12. Thecentral jaw it has laterally extending lugs 14 on one side thereof whichare vertically staggered with respect to, and interfit with, similarlugs 15 on the adjacent end of the slip jaw ill. The adjacent lugs 14-and 15 are hinged together by a hinge pin 16 extending therethrough sothat the slip jaw ll may pivot or swing laterally relative to thecentral jaw ii Lugs 17 are provided on the side of the central jawopposite from the lugs 14 and are similar in construction. These lugs 17interfit and are vertically staggered with respect to lugs 18 on theadjacent side of the slip jaw 12 with a hinge pin 19 providing theconnection between the adjacent lugs 17 and 18, whereby pivotal swingingof the slip jaw 12 with respect to the central jaw it) is made possible.Thus, the slip A of this invention provides for the lateral swinging orpivoting of the end jaws it and 12 with respect to the central jawwhereby a pipe i may be gripped by the slip to prevent movement thereof.The extent of outward opening of the end jaws ill and 12 is limited bystop ears Ztl) on the central jaw and 21 and 22 on the end jaws 11 and12, respectively. The extent of inward swinging of the end jaws iii andi2 is determined by the stop ear 23 and 24 on ti e and jaws iii. and 12,respectively, such ears 23 and 24- being spaced vertically with respectto each other so that the bodies of the jaws will be contacted by theears. Thus, although the slip A of this invention is adapted to gripvarious sizes of pipe P, the stop ears serve to limit the various sizesof pipes which the slip can effectively grip to thereby assure that theproper size of the slip A is used with a particular pipe.

Each of the slip jaws 1t), 11 and 12 are substantially identical exceptfor the arrangement of the hinge lugs and the stop ears previouslydescribed. Therefore, only the details of the slip jaw 12 will beexplained, since such details are applicable to the slip jaws lit and11, as well as the slip jaw 12. The body of the slip jaw 12, as bestillustrated in Figures 3 and 4, has a recess R in its inner surface 25,which recess R has a back or rear wall 26, a bottom wall 27, a top wall28, and side walls 29 and lit); The inner surface 25 and the inner orrear wall 26 of the recess R are actually formed on the front wall orplate F of the slip jaw body, which front plate F is connected to a reardownwardly inclined plate or wall 30 of the body by end or side plates31 and 32. The upper end of the body which may be referred to as a capportion comprises the wall section 33 which is connected between theside plates and which has its lower inner edge forming the top wall 28of the recess R. A lateral top plate 33a projects laterally between theside plates, and the front wall, rear wall and cap portion may all bemade integral as by casting or if desired may be fabricated and welded.

The back or rear plate 30 of the body is inclined downwardly for fittingwithin the conventional slip bowl (not shown), and the upper end of therear plate 30 has an opening 34 while the lower end of the plate 30 hasan opening 35 therein, which openings communicate with a verticalpassage 36 between the front plate F and the rear or back plate 30,whereby mud or slush may flow through the passage 36 When the slip A isin a slip bowl in gripping contact with the pipe. The front wall F mayalso be provided with an opening 37 at its lower end which alsocommunicates with the vertical flow passage 36 for the flow of mud orslush therethrough.

As shown in Figure 5, dogs 40 are arranged in a vertical stack in therecess R with the lower dog in the stack resting upon the bottom wall 27of the recess and the upper dog in the stack being spaced verticallydownwardly from the top wall 28 of the recess. The dogs 40 are of aparticular con truction which will be described in detail hereinafter,but generally they may be referred to as rolling dogs since they areadapted to roll or tilt upwardly upon movement of a pipe upwardly incontact with the teeth thereof. The rear surfaces of the dogs 40 contacta Wear plate 41 positioned against the inner wall 26 of the recess R.This wear plate 41 is of a slightly softer material than the material ofthe dogs 40, whereby the wear during the tilting or rolling of the dogs40 will be on the plate 41 rather than the rear surfaces of the dogs 40,as well as to provide for a slight indentation of the plate 41 by thedogs 4 to compensate for any irregularities in the surface of the pipeor the width of the dogs themselves, whereby uniform contact of theteeth of the dog with the pipe is effected.

The stack of dogs are held in the recess R by a dog retainer element Dpositioned in contact with the upper dog in the stack and spacedslightly below the top wall 28 of the recess R. The dog retainer D(Figure 6) has a vertical generally arcuate part or portion 42 with thelower end 42a thereof contacting the upper dog in the stack. Extendingrearwardly from the vertical portion 42 is a lateral section or arm 43which is substantially perpendicular to the vertical section 42 and isof a reduced width as compared to the vertical section 4-2. This lateralsection 4-3 fits within a lateral slot 4 in the body of the slip jaw,such lateral slot being formed by a rearwardly extending flange 45forming the bottom wall or surface of the slot 44 and having connectionwith the front wall F of the body, with the top surface or wall of theslot 44 being formed by a rearwardly extending flange 46 substantiallyparallel to the flange 45 and being a continuation of the upper or topwall 2% of the recess R. The flanges 45 and 46 may be cast integral withthe body and are actually a part thereof. The lateral slot 44 opens intothe upper end of the recess R and is adapted to receive the lateral armor section 43 of the dog retainer D. When the dog retainer D isassembled with the body (Figure 5), it is urged downwardly into constantengagement with the upper dog by a leaf spring 43 which has a reversebent end 49 which fits underneath a downward projection 43a at the outerend of the lateral arm 43. The forward end 50 of the spring 48 contactsthe upper surface 43b of the lateral arm i3 so that when the dogretainer D and the spring 4% are assembled and held in the slot 44 bythe cotter pin 52 extending through the aligned openings 53 and Se inthe spring 4-8 and the lateral arm 43, respectively, the upper surface455a of the spring 43 contacts the flange 46, whereby the spring 48 ismaintained under a slight compression at all times. It will be observedthat the openings 53 and 5d are of a slightly larger diameter than theexternal diameter of the cotter pin 52. This permits the dog retainer Dto move upwardly without interference from the cotter pin 52 and alsopermits a lateral sliding movement of the spring 48 relative to the arm43 and toward the shoulder 4212 as the dog retainer D moves upwardly forcontact with the upper wall 28. It will be observed that the downwardprojection 43a serves as a fulcrum point for the rocking or pivotalmovement of the dog retainer D which moves in response or in accordancewith the tilting or rolling of the dogs 4%).

An important feature of this invention is the fact that the upper wall28 of the recess R completely overlies, or extends inwardlysubstantially the same distance as, the dog retainer D so that the upperwall 28, which is part of the body of the slip jaw, limits the upwardmovement of the dog retainer D by abutment therewith to thereby preventthe upward bending of such dog retainer. it will be observed that thelower wall 27 of the recess R is inclined inwardly and upwardly at abouta ten degree angle so as to cant the dOgs 4t) upwardly, and that thelower end 42a of the dog retainer D is similarly inclined whereby uponthe rolling or tilting of the dogs 40 and a consequent rocking orpivotal movement of the dog retainer D about its fulcrum point, the dogs40 are securely held at all times in the recess R with the lower end 42aof the dog retainer D being constantly in engagement with the upper dogin the stack.

The dogs themselves are shown in detail in Figures 7-9, each dog 40having a forward arcuate edge 50 with two rows 51 and 52 of pipeengaging teeth which are symmetrically disposed on the forward arcuateedge of the dog plate (Figure 8). The corners 53 and 54 formed at theintersection of the rear surface 55 of the plate with the top surface 56and the bottom surface 57 are rounded to permit the dog to roll or tiltand also so that the dog is reversible. Thus, with the particularconstruction of the dog 40, namely, with the two rows of symmetricallydisposed gripping teeth onthe forward arcuate edge of the plate and therounded rear corners 53 and 54, each of the dogs 46 may be used witheither the row 51 of teeth or the row 52 of teeth disposed upwardly.Thus, assuming that the dogs have been used for a period of time withthe row 51 of the gripping teeth disposed upwardly and have beensubjected to considerable wear, the dog may then be reversed so that therow 52 of teeth is positioned upwardly whereby such row will thenreceive the majority of the wear. it will also be noted that the sides58 and 59 of the dog 48 are flared rearwardly and that the walls 29 andof the recess R in the body must have a corresponding inclination oroutward flaring, JhlCh further assists in retaining the dogs 40 in therecess. Because of the flared ends or sides 58 and 59, to assemble thedogs 40 in the recess they must be cocked at an angle to the verticalfor insertion, and this is possible because even the upper dog in thestack is spaced somewhat below the top wall 28 of the recess and thereis, therefore, sufficient space for such cocking of the dogs duringinsertion,

As has been explained, the cap portion C is part of the slip jaw bodyand has a hollow portion or space below the top plate 33a. An opening 61in the top plate 33a is formed in order to drill downwardly through thelateral flanges 45 and 46 to form the openings therein for receiving thecotter pin 52. The side or end plate 31 has an opening 62 therein belowthe top plate 334: and the end plate 32 has a similar opening 63therein. These openings 62 and 63 are in the same lateral plane andreceive the end pins 64 and 65 of a. trunnion 66 having connection witha handle 67 (Figure 1). The trunnion 66 for the handle 67 is thuspivotally connected to the body of the slip jaw through the end pins 64and 65, with the pivotal connection being disposed below the top plate33a for protection against impacts or blows which may be applied to thebody of the slip jaw. This often occurs in the lowering of pipe due tothe inadvertent release of the elevators lowering the pipe, whereby theelevators hit the top plate 330 with a terrific blow which would damagethe pivotal connection for the handle unless such protection of the topplate is provided. The handles 68 and 69 on the jaws 11 and 10,respectively, are connected in the same manner as the handle 67 on theslip jaw 12. The handle 69 on the central jaw extends substantiallyperpendicular to the trunnion thereof, while the handles 67 and 68 arebent so as to extend substantially parallel to the trunnion, whicharrangement provides for easier movement of the handles 67 and 68 towardeach other for closing the slip about the pipe P. All of the handles arepivoted so that they will move downwardly below the lateral plane of thetop plate 33a of each of the slip jaws whereby they will be below, andprotected by said top plates against impacts from the elevators orsimilar means.

In the use of the slip A of this invention, it is placed in aconventional slip bowl with the' pipe P extending between the jaws(Figure 1). The end jaws 11 and 12 are moved toward each other so as topermit the dogs 40 to grip the pipe P to prevent downward movement ofthe pipe. With the rolling dog construction, the pipe P may be movedupwardly without releasing or moving the slips, because as the pipemoves upwardly, even though it is in contact with the teeth of the dogs,the dogs will tilt or roll upwardly to permit the upward release andmovement of the pipe P. Upon the upward tilting of the dogs 40, the dogretainer D will rock or pivot about its fulcrum point between theprojection 43a and the bottom flange 45 with the upward movement of thearcuate portion 42 being limited by the top wall 28 of the recess.

The space between the upper surface of the portion 42 of the retainerand the top wall 28 is such that the retainer may undergo the movementnecessary during normal upward movement of the pipe and during normaloperations the retainer does not engage the top wall 28 with anyappreciable force. However, in the event a sharp upward thrust, jar orblow is applied to the dogs by a collar on the pipe striking same, suchthrust, jar or blow will rock the dog retainer D upwardly against thetop wall 28 and since the dog retainer is confined entirely therebelow,the impact is transmitted to the slip jaw body which comprises the mainportion of the unit and is of sutficiently heavy material and hassufiicient strength to absorb the blow. Thus, the retainer is notrequired to absorb or withstand these upward jars and merely functionsas an intermediate element through which the impact is transmitted fromthe dogs directly to the jaw body. This arrangement prevents bending,deformation or damage to said retainer.

The spring 48 will constantly maintain the bottom surface 42a of the dogretainer D in contact with the upper dog in the stack so that the dogs40 are prevented from turning or falling out of the recess R duringtheir tilting or rolling movement. When it is desired to replace thedogs or to reverse same, the cotter pin 52 is readily accessible to theopening 34 whereby the removal of the dog retainer D and the dogs 40 isfacilitated.

It should be pointed out that although the particular construction ofthe hinges between the slip jaws as shown in the drawings locates thesame between the upper lateral plane of the stack of dogs and the lowerlateral plane of the stack of dogs to reduce the moment couple or torqueexerted on the hinges, such construction is not required, as anysuitable arrangement of the hinges with respect to the stack of dogs canbe utilized within the scope of this invention.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made, within the scope of the appended claimwithout departing from the spirit of the invention.

What is claimed is:

In a slip adapted to engage a pipe to prevent movement thereof, a slipjaw having a body with an arcuate inner surface, said body having alongitudinal recess in said inner surface, a stack of pipe-gripping dogswhich are constructed for tilting or rolling being disposed in saidrecess and extending beyond said inner surface, the lower dog in thestack resting on the bottom wall of the recess and the upper dog beingspaced from the top wall of the recess, a dog retainer positioned incontact with said upper dog to prevent displacement, of said dogs fromsaid recess, a pivotal connection between said dog retainer and saidbody to provide for pivotal movement of said retainer as said dogs rollor tilt in said recess, said body having a lateral slot opening into theupper end of the inner wall of said recess, and said dog retainer havinga lateral portion thereof extending into said slot, said lateral portionof said retainer having a projection thereon in contact with the bottomwall of said lateral slot to provide the fulcrum point for said pivotalmovement of said dog retainer.

References Cited in the file of this patent UNITED STATES PATENTS1,400,701 Vreeland Dec. 20, 1921 1,907,685 Tilbury May 9, 1933 1,908,652Adair May 9, 1933 1,999,279 Burns .Apr. 30, 1935 2,030,499 Church Feb.11, 1936 2,245,979 Johnson June 17, 1941 2,274,273 Miller Feb. 24, 19422,288,851 Sharp July 2, 1942

